package cn.zuoyewanshang;

public class Erbei {
	public static void main(String[] args) {
		int	num=0;
		for(int i=0;i<101;i++) {
			int mun=i%2;			
			if(mun >0 ) {
			num=num+i;
			}
		}
		System.out.println(num);
	}

}
